The invention relates to a device on a handheld cutting or sawing machine with a rotatable cutting or sawing blade; a driving machinery for rotating the blade; means for supplying cooling or flushing water on the blade and/or a workpiece; a rear handle with controls for the driving machinery; a front handle bow with a front part which is the normal gripping part of the handle bow; a right hand side part and a left hand side part; and a water valve for control of the flow of cooling or flushing water, said valve comprising a valve housing with a valve house chamber; a valve body which is turnable about an axis of rotation by means of a lever; an inlet nipple for the connection of a water hose for incoming water to the valve; and an outlet nipple for the connection of a water hose for outgoing water from the valve; and securing means for mounting the water valve on the handle blow.
Various embodiments of devices of the above mentioned type are known in the art. Typically, the valves which are included in the device are standard type valves and have comparatively small outer dimensions and are placed so that the operator shall not unintentionally touch the valve during operation. This principle, however, has caused a number of inconveniences. Some of them shall be mentioned here. Because the valve is placed so that it is difficult to find, the operator must keep his left hand about the gripping part of the handle bow and manipulate the valve with his right hand, which means that he has to leave his hold of the rear handle and hence also leave his access of the controls for the driving machinery. This in other words means that he cannot control the flow of water at the same time as he operates the machine. This is a serious drawback because the type of work often makes it desirable to be able to vary the flow of water during operation, e.g. to increase the flow of water as the cutter blade successively cuts deeper and deeper in a workpiece and the kerf is being filled with cuttings. The more or less hidden location of the valve also makes it impossible for the operator to read the setting of the valve during work. Another inconvenience with today""s devices, where the inlet and the outlet of the valve have the same direction, is that they, although the water valve is placed so that it is difficult to access, do not make it possible to guide the hose from the valve to the exit nozzle in such a way that problems can be avoided. To the contrary, such problems are frequent in connection with existing machines and cause inconveniences during operation of the machine. For example, the hose may hinder the operator in his work as he shall grip about the gripping part of the handle bow, and this is particularly true when he uses thick mittens, which he does as a rule. In connection with some machine designs, the hose also can be damaged through contact with the exhaust muffler of the machine, when the muffler is located between the engine and the cutter blade, and the cutter blade is provided with a guard, which can be moved backwards towards the hose. Other problems and inconveniences are related to the design and mounting of the valve.
The purpose of the invention is to address the above mentioned complex of problems. More particularly, the invention aims at providing one or more of the following advantages or improvements:
To make it possible for the operator to reach the turning device of the water valve with any of the fingers of his left hand without leaving his hold of the gripping part of the handle bow and thus be able to adjust the flow of water accurately during operation. This implies for instance that the operator can increase the flow of water in order to flush the kerf clean, if the kerf tends to be filled with cuttings and vice versa to reduce the flow when the kerf has been rinsed, or to reduce the flow in order e.g. to avoid violent splashes from the blade, especially when the blade not yet has reached any greater cutting depth.
To be able during operation to read the turning device""s setting, which represents a certain flow of water for every pressure of incoming water to the valve.
To provide a device which makes it easy guide run the water hose from the valve, independent of the entrance direction to the valve, in such a way that the hose does not make any serious hinder for the operators work and/or so that the hose will not be damaged during any movements of the operation of the machine.
To design the valve so that it does not restrict the operator""s normal use of the handles.
To provide a valve which is easy to set and to adjust to different pressures of incoming water, and which preferably displays a large and clear angle difference between different settings, which represent different flows of water.
To provide a water valve which is robust and impact resistant.
To provide a valve having an outward appearance which is substantially void of sharp edges and projecting parts, which could hurt the operator, and/or in which his clothings could get caught, and/or which could cause other damages.
To provide a water valve which can be employed as a standard element for many types of cutting or sawing machines of the above mentioned kind.
To provide a valve which is easy to mount.
To provide a valve which is cheap to manufacture.
One or more of the above advantages or improvements can be achieved therein that the invention is characterised by what is stated in the characterising part of claim 1. Other advantages and improvements can be achieved therein that the invention is characterised by that is stated in the subsequent patent claims. Other features and aspects of and advantages or improvements which can be achieved through the invention will be apparent from the following description of a preferred embodiment.